The present invention relates generally to surgical tissue retractors and specifically to retractors that may be used to enlarge a surgical incision or a natural body opening. Retraction of a surgical incision or body opening is generally accomplished by placing a first, flexible retention member through the incision or body opening and into a body cavity, such as an abdominal cavity, and subsequently tensioning the first retention member against the inner portion of the associated body wall adjacent to the incision or opening by applying tension to a sleeve that is coupled to the first tension member. The sleeve may be tensioned by winding it upon an external, more rigid structure. As the sleeve is wound around the external structure, the incision or opening is reshaped and/or enlarged to a substantially round condition.